Compound shimming

ABSTRACT

Disclosed herein is a method. The method includes identifying a first location on a first part to place a first shim tab to form a first portion of a compound shim. The method also includes applying the first shim tab to the first location on the first part with an end-effector. The method also includes identifying a second location directly adjacent to the first location on the first part to place a second shim tab. The method also includes applying the second shim tab to the second location on the first part with the end-effector to form a second portion of the compound shim. The method also includes applying a third shim tab to the second shim tab at the second location to increase a thickness of the second portion of the compound shim.

FIELD

This disclosure relates generally to component joining, and moreparticularly to joint shimming and filling.

BACKGROUND

Today, many complex structures, such as aircraft, spacecraft,automobiles, and the like, are made by assembling individual components.Those assembled materials include a significantly large number ofinterconnected components. The interconnected components of complexstructures are connected together at joints. The joints of complexstructures are traditionally formed using fasteners and weldments.

To improve the characteristics of joints, gaps between components arefilled or shimmed to reduce the stresses and other forces experienced bythe fasteners, weldments, and components of the structures. However,exact component geometries can vary making it difficult to fit a gapwith prebuilt shims and fillers.

SUMMARY

The subject matter of the present application has been developed inresponse to the present state of the art, and in particular, in responseto the shortcomings of traditional shimming and filling methods andsystems, that have not yet been fully solved by currently availabletechniques. Accordingly, the subject matter of the present applicationhas been developed to provide a shimming method, and associated systems,that overcome at least some of the above-discussed shortcomings ofprior-art techniques.

Disclosed herein is a method. The method includes identifying a firstlocation on a first part to place a first shim tab to form a firstportion of a compound shim. The method also includes applying the firstshim tab to the first location on the first part with an end-effector.The method also includes identifying a second location directly adjacentto the first location on the first part to place a second shim tab. Themethod also includes applying the second shim tab to the second locationon the first part with the end-effector to form a second portion of thecompound shim. The method also includes applying a third shim tab to thesecond shim tab at the second location to increase a thickness of thesecond portion of the compound shim. The preceding subject matter ofthis paragraph characterizes example 1 of the present disclosure.

The first shim tab and the second shim tab in the compound shim areseparated by a gap less than a width of the first shim tab. Thepreceding subject matter of this paragraph characterizes example 2 ofthe present disclosure, wherein example 2 also includes the subjectmatter according to example 1, above.

The method further includes determining a surface characteristic of thefirst part. The preceding subject matter of this paragraph characterizesexample 3 of the present disclosure, wherein example 3 also includes thesubject matter according any one of examples 1-2, above.

The method further includes determining a surface characteristic of asecond part to be joined to the first part and determining a geometry ofthe compound shim based on the surface characteristic of the first partand the surface characteristic of the second part. The preceding subjectmatter of this paragraph characterizes example 4 of the presentdisclosure, wherein example 4 also includes the subject matter accordingto example 3, above.

Applying the first shim tab further includes removing the first shim tabfrom a carrier material. The preceding subject matter of this paragraphcharacterizes example 5 of the present disclosure, wherein example 5also includes the subject matter according to any one of examples 1-4,above.

The method further includes separating the first shim tab from thesecond shim tab during the application of the first shim tab to thefirst location with the end-effector. The preceding subject matter ofthis paragraph characterizes example 6 of the present disclosure,wherein example 6 also includes the subject matter according to any oneof examples 1-5, above.

Applying the first shim tab includes adhering the first shim tab to thefirst part with an adhesive. The preceding subject matter of thisparagraph characterizes example 7 of the present disclosure, whereinexample 7 also includes the subject matter according to any one ofexamples 1-6, above.

Also disclosed herein is an apparatus. The system includes a supplystructure and an applicator. The supply structure carries a first shimtab, a second shim tab, and a third shim tab. The applicator is toreceive the first shim tab from the supply structure, apply the firstshim tab to a first location on a part, receive the second shim tab fromthe supply structure, apply the second shim tab to a second locationdirectly adjacent to the first location on the part to for a compoundshim, receive the third shim tab from the supply structure, and applythe third shim tab to the second shim tab at the second location. Thepreceding subject matter of this paragraph characterizes example 8 ofthe present disclosure.

The apparatus further includes a collection structure to collect acarrier material. The preceding subject matter of this paragraphcharacterizes example 9 of the present disclosure, wherein example 9also includes the subject matter according to example 8, above.

At least one of the supply structure and the collection structureincludes a spool. The preceding subject matter of this paragraphcharacterizes example 10 of the present disclosure, wherein example 10also includes the subject matter according to example 9, above.

Applying the first shim tab, the second shim tab, and the third shim tabincludes separating the first shim tab, the second shim tab, and thethird shim tab from a carrier material. The preceding subject matter ofthis paragraph characterizes example 11 of the present disclosure,wherein example 11 also includes the subject matter according to any oneof examples 8-10, above.

Applying the first shim tab include separating the first shim tab fromthe second shim tab. The preceding subject matter of this paragraphcharacterizes example 12 of the present disclosure, wherein example 12also includes the subject matter according to any one of examples 8-11,above.

A control module to control delivery of the first shim tab, the secondshim tab, and the third shim tab to the applicator. The precedingsubject matter of this paragraph characterizes example 13 of the presentdisclosure, wherein example 13 also includes the subject matteraccording to any one of examples 8-12, above.

Applying the third shim tab to the second shim tab increases thethickness of the compound shim at the second location. The precedingsubject matter of this paragraph characterizes example 14 of the presentdisclosure, wherein example 14 also includes the subject matteraccording to any one of examples 8-13, above.

At least two of the first shim tab, the second shim tab, and the thirdshim tab have a uniform geometry to facilitate a tessellated pattern onthe part. The preceding subject matter of this paragraph characterizesexample 15 of the present disclosure, wherein example 15 also includesthe subject matter according to any one of examples 8-14, above.

Applying the first shim tab, the second shim tab, and the third shim tabincludes separating the first shim tab, the second shim tab, and thethird shim tab from a carrier material. The preceding subject matter ofthis paragraph characterizes example 16 of the present disclosure,wherein example 16 also includes the subject matter according to any oneof examples 8-15, above.

Also disclosed is a system. The system includes an assembly jig, aninspection module, a control module, a multi-axis arm, and anend-effector. The assembly jig is to secure a first part. The inspectionmodule is to generate inspection data describing a surfacecharacteristic of at least the first part at a joining region where thefirst part is to be joined with a second part. The control module is togenerate a compound shim plan corresponding to the joining region of thefirst part based on the inspection data. The multi-axis arm is to morerelative to the assembly jig in response to input from the controlmodule. The end-effector is coupled to the multi-axis arm to receive afirst shim tab at an applicator of the end-effector, align theapplicator with the joining region on the first part, apply the firstshim tab to the joining region of the first part at a first location ofthe compound shim plan with the applicator, receive a second shim tab atthe applicator of the end-effector, apply the second shim tab to thejoining region of the first part at a second location of the compoundshim plan with the applicator, the second shim tab forming a patternwith the first shim tab, receive a third shim tab at the applicator ofthe end-effector, and apply the third shim tab to the second shim tab atthe second location of the compound shim plan with the applicator toincrease a thickness at the second location according to the compoundshim plan. The preceding subject matter of this paragraph characterizesexample 17 of the present disclosure.

The inspection module is further to monitor the application of the firstshim tab to adjust the application of the second shim tab. The precedingsubject matter of this paragraph characterizes example 18 of the presentdisclosure, wherein example 18 also includes the subject matteraccording to example 17, above.

The control module is further to control delivery of the first shim tab,the second shim tab, and the third shim tab to the applicator. Thepreceding subject matter of this paragraph characterizes example 19 ofthe present disclosure, wherein example 19 also includes the subjectmatter according to any one of examples 17-18, above.

The joining region includes a fastener location to facilitate a fastenerto join the first part with the second part. The preceding subjectmatter of this paragraph characterizes example 20 of the presentdisclosure, wherein example 20 also includes the subject matteraccording to any one of examples 17-19, above.

The described features, structures, advantages, and/or characteristicsof the subject matter of the present disclosure may be combined in anysuitable manner in one or more embodiments and/or implementations. Inthe following description, numerous specific details are provided toimpart a thorough understanding of embodiments of the subject matter ofthe present disclosure. One skilled in the relevant art will recognizethat the subject matter of the present disclosure may be practicedwithout one or more of the specific features, details, components,materials, and/or methods of a particular embodiment or implementation.In other instances, additional features and advantages may be recognizedin certain embodiments and/or implementations that may not be present inall embodiments or implementations. Further, in some instances,well-known structures, materials, or operations are not shown ordescribed in detail to avoid obscuring aspects of the subject matter ofthe present disclosure. The features and advantages of the subjectmatter of the present disclosure will become more fully apparent fromthe following description and appended claims, or may be learned by thepractice of the subject matter as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of the subject matter may be more readilyunderstood, a more particular description of the subject matter brieflydescribed above will be rendered by reference to specific embodimentsthat are illustrated in the appended drawings. Understanding that thesedrawings depict only typical embodiments of the subject matter and arenot therefore to be considered to be limiting of its scope, the subjectmatter will be described and explained with additional specificity anddetail through the use of the drawings, in which:

FIG. 1 is a schematic perspective view of a compound shim, according toone or more examples of the present disclosure;

FIG. 2 is a schematic side view of an end-effector arrangement,according to one or more examples of the present disclosure;

FIG. 3A is a schematic perspective view of a roll of a plurality of shimtabs on a carrier material, according to one or more examples of thepresent disclosure;

FIG. 3B is a schematic top view of a plurality of unseparated shim tabs,according to one or more examples of the present disclosure;

FIG. 4 is a schematic side view of a compound shimming system, accordingto one or more examples of the present disclosure; and

FIG. 5 is a schematic flow diagram of a method, according to one or moreexamples of the present disclosure.

DETAILED DESCRIPTION

Reference throughout this specification to “one embodiment,” “anembodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment of the present disclosure.Appearances of the phrases “in one embodiment,” “in an embodiment,” andsimilar language throughout this specification may, but do notnecessarily, all refer to the same embodiment. Similarly, the use of theterm “implementation” means an implementation having a particularfeature, structure, or characteristic described in connection with oneor more embodiments of the present disclosure, however, absent anexpress correlation to indicate otherwise, an implementation may beassociated with one or more embodiments.

Embodiments described below relate to forming a compound shim by placingshim tabs on a part at a joining region (where two parts may or aredesigned to meet). The compound shim can be adapted in footprint (e.g.,size) and thickness to provide a variety of shimming sizes and shapes(e.g., 3-dimensional shapes) by changing the number of shim tabs appliedto the part, the spacing/pattern of the shim tabs, and the stackingdepth of the shim tabs. Other embodiments are described below withrespect to the several Figures.

The illustrated embodiment of FIG. 1 includes a plurality of shim tabs102-108 that form a compound shim 100 applied to a part 110 (alsoreferred to below as a “first part 110”). In some embodiments, each ofthe shim tabs 102-108 have the same geometry. In the illustratedimplementation, the shim tabs 102-108 have a hexagonal geometry. Inother implementations, the shim tabs 102-108 have a regular or irregularnon-hexagonal geometry (e.g., triangular).

In some embodiments, the shim tabs 102-108 are phenolic shim tabs. Inother embodiments, the shim tabs 102-108 include one or more metallic,ceramic, plastic, or other synthetic or natural materials.

Each of the shim tabs 102-108 has a thickness. In some embodiments, theshim tabs 102-108 have a thickness of approximately three-thousandths ofan inch (i.e. 0.003 inches). In other embodiments, the shim tabs 102-108are thicker or thinner than three-thousandths of an inch. In someembodiments, the thickness of each shim tab 102-108 is uniform. In otherembodiments, at least one of the shim tabs 102-108 has a non-uniformthickness. In some embodiments, the shim tabs 102-108 have a genericshape and the same thickness. In other embodiments, one or more of theshim tabs 102-108 has a thickness different from another of the shimtabs 102-108.

In the illustrated embodiment, each of the shim tabs 102-108 are layeredto a corresponding depth or thickness. The middle stack 102A of shimtabs 102 has multiple shim tabs 102 stacked together to increase theoverall thickness of the corresponding portion of the compound shim 100.In some embodiments, the shim tabs 102-108 are stacked using anadhesive. In other embodiments, the shim tabs 102-108 are joined in astack with other chemical, mechanical, thermal, or electric adhesion.

In the illustrated embodiment, the shim tabs 102 of the middle stack102A are shown with their geometries aligned with one another in auniform stack. In other embodiments, the shim tabs 102 are stacked toachieve a non-uniform stack; for example, stacked in alternatingrotational positions. In the illustrated embodiment, the shim tabs 102of the middle stack 102A are stacked in a linear stack. In otherembodiments, the shim tabs 102 have one or more shim tabs 102 that arenot linearly stacked. For example, the shim tabs 102 may include one ormore shim tabs 102 which engage a proximal stack 104A of shim tabs 104.Linking shim tab stacks may provide structural stability and/or allowfor creation of a certain overall geometry in the compound shim 100.

In the illustrated embodiment, the proximal stacks 104A of shim tabs 104each include, for example, four shim tabs 104 stacked together, whilethe middle stack 102A of shim tabs 102 includes, for example, six shimtabs 102. In some embodiments, the difference in height between themiddle stack 102A of shim tabs 102 and the proximal stack 104A of shimtabs 104 is determined based on the curvature or difference in surfacecharacteristics in the part 110. In another embodiment, the differencein height between the middle stack 102A of shim tabs 102 and theproximal stacks 104A of shim tabs 104 is determined based on acombination of one or more surface characteristics of the first part 110and one or more surface characteristics of a second part where the firstpart 110 and the second part are to be joined or are to intersect.

In some embodiments, the shim tabs 104 of the proximal stacks 104A areplaced directly adjacent to the shim tabs 102 of the middle stack 102A.In some embodiments, the term “directly adjacent” refers to arrangingthe shim tabs next to each other to define a gap. In some embodiments,the gap is less than a width of a shim tab. In other embodiments, thegap is sized to accommodate placement of the shim tabs based on thecompound shim plan which may be adjusted to a surface characteristic ofthe first part 110. In some embodiments, the gap is uniform around eachshim tab. In other embodiments, the gap varies by location within thecompound shim 100.

The illustrated embodiment also includes intermediate stacks 106A ofshim tabs 106. While the illustrated embodiment includes two shim tabs106 layered to form the intermediate stacks 106A, other embodimentsinclude fewer or more shim tabs 106 in each intermediate stack 106A. Theillustrated embodiment further includes distal shim tabs 108. In theillustrated embodiment, the distal shim tabs 108 are single unstackedshim tabs applied to the first part 110.

While the illustrated embodiment includes a concentric pattern of shimtabs, other embodiments have other arrangements with different stackthicknesses in different regions of the compound shim 100. In someembodiments, the shim tabs of the compound shim 100 are orientedsimilarly. In other embodiments, the orientation of at least one shimtab or shim tab stack is different from another shim tab or shim tabstack. In the illustrated embodiment, the compound shim 100 is formed oftessellated shim tabs of a single or similar geometries. In otherembodiments, the compound shim 100 is formed using shim tabs havingdifferent geometries.

FIG. 2 is a schematic view of an end-effector arrangement 200, accordingto one or more examples of the present disclosure. The end-effectorarrangement 200 includes a robotic arm 202 to which an end-effector 204is coupled. The end-effector 204 includes a supply structure 206, anapplicator 208, and a collection structure 210. The robotic arm 202 iscapable of positioning the end-effector 204 to apply a shim tab to apart. The robotic arm 202 is capable of movement in one or moredirections. Moreover, the robotic arm 202 is numerically or computercontrolled.

In some embodiments, the end-effector 204 is capable of movement in oneor more directions. In some embodiments, the movement capabilities ofthe end-effector 204 are complimentary to the movement capabilities ofthe robotic arm 202. In the illustrated embodiment, the end-effector 204includes an extension structure 212 to extend a portion of theend-effector 204 relative to the robotic arm 202. The relative extensionof a portion of the end-effector 204 is described in greater detailbelow.

In some embodiments, the end-effector 204 carries shim tabs on thesupply structure 206. The supply structure 206 in the illustratedembodiment is a spool with shim tabs contained on the spool. In otherembodiments, the supply structure 206 includes a container such as abox, a roll, or other structure capable of storing and handling shimtabs. In the illustrated embodiment, the movement of the supplystructure 206 is monitored and/or controlled by a control module 214. Inthe illustrated embodiment, the control module 214 is coupled to thesupply structure 206. In some embodiments, the control module 214includes a motor to drive the supply structure 206 or measure adisplacement of the supply structure 206.

The supply structure 206 is capable of receiving a pre-loaded roll ofshim tabs. In another embodiment, the supply structure 206 is capable ofwinding an organization of shim tabs onto the supply structure 206.Embodiments of the shim tab organization are described in greater detailbelow with reference to FIGS. 3A and 3B. The supply structure 206dispenses the shim tabs 216 for application on a part. The end-effector204 includes guide elements 218. The guide elements 218 align andsupport the shim tabs 216 from the supply structure 206 to theapplicator 208 and from the applicator 208 to the collection structure210. The guide elements 218 apply tension to the shim tabs 216. Theguide elements 218 include wheels or rollers. In other embodiments, theguide elements 218 are non-rolling glide surfaces or channels. Otherembodiments of the guide elements 218 include other structures.

The guide elements 218 direct the shim tabs 216 to the applicator 208.The applicator 208 forms a point at which a shim tab is applied to asurface of a part. The applicator 208 includes a wheel or roller 220 toreceive the shim tabs 216 and apply a shim tab to a part. The roller 220may be rigid or flexible. In some embodiments, the roller 220 is capableof deformation to facilitate application of the shim tab to a part. Theroller 220 is indexed, in some implementations, for tracking a positionof the shim tab relative to the applicator 208.

The applicator 208 is extendable through actuation of the extensionstructure 212. For example, if the extension structure 212 is actuated,the applicator 208 may be extended away from the robotic arm 202 toapply a shim tab. Other functionality such as rotation and flexure mayalso be incorporated with the applicator 208 independently or inconjunction with the extension structure 212.

A spent carrier material 222 is returned from the roller 220 to thecollection structure 210. The collection structure 210 may be similar tothe supply structure 206 described above. The collection structure 210includes a control module 214, as described above, to control and/ortrack the movement of the collection structure 210. The carrier material222 may be a release liner or frame on which the shim tabs are disposeduntil application of the shim tabs by the applicator 208 to a part. Thecarrier material 222 is guided by guide element 218 on the way to thecollection structure 210. As shown, the end-effector 204 includes atensioner device 224 to apply tension to the carrier material 222. Otherembodiments may include fewer or more components than illustrated.

FIG. 3A is a schematic view of a roll 300 of a plurality of shim tabs302 on a carrier material 304, according to one or more examples of thepresent disclosure. The shim tabs 302 are disposed on an outer surfaceof a carrier material 304 that is wound to form the roll 300. The shimtabs 302 include an adhesive or other material to lightly or firmlysecure the shim tabs 302 to the carrier material 304. The adhesive orother material to secure the shim tabs 302 is applied to the carriermaterial 304 prior to or at the time of application of the shim tabs 302to the carrier material 304.

The shim tabs 302 are formed prior to being applied to the carriermaterial 304. However, in other embodiments, the shim tabs 302 areformed on the carrier material 304. Some or all of the roll of shim tabs302 on the carrier material 304 are uniform in shape and size. In otherembodiments, one or more of the shim tabs 302 differs in shape or sizefrom another of the shim tabs 302 on the carrier material 304.

In some embodiments, the carrier material 304 has an anti-stick coatingor characteristic to facilitate removal of the shim tabs 302 on one orboth sides of the carrier material 304. For example, the carriermaterial 304 may have anti-stick properties on the front of the carriermaterial to facilitate removal of the shim tabs 302 during applicationor on the back of the carrier material 304 to reduce sticking of theshim tabs 302 to the backside of the carrier material when wound on theroll 300. In some embodiments, the shim tabs 302 are separated by a gapon the carrier material 304. In other embodiments, the shim tabs 302 arein contact with one another on the carrier material 304.

In the illustrated embodiment, the roll 300 is open at the center tofacilitate mounting the roll 300, for example, on a supply structure(e.g., the supply structure 206 of FIG. 2). In other embodiments, theroll 300 has no, or a relatively small, opening at the center. In someembodiments, the roll 300 includes an indexing indicator on the shimtabs 302, the carrier material 304, or other location on the roll 300.In some embodiments, the roll 300 includes perforations, notches, orother physical characteristics to facilitate winding or unwinding of theroll 300 or to apply the shim tabs 302.

FIG. 3B is a schematic view of a plurality of unseparated shim tabs 302,according to one or more examples of the present disclosure. In theillustrated embodiments, shim tabs 302 are connected to one another.Connection of the shim tabs 302 facilitates application to or removalfrom a carrier material. Alternatively, the connection of the shim tabs302 removes the need for a carrier material (i.e. carrier material 304of FIG. 3A).

The shim tabs 302 are connected via a connection structure 306. Theconnection structure 306 may be material added to connect the shim tabs302 or may be locations on the shim tabs 302 where the material of theshim tabs 302 is connected without additional material. In someembodiments, the connection structure 306 has a reduced thickness or anincluded weakness to facilitate separation of the shim tabs 302. In someembodiments, the shim tabs 302 are connected at the connection structure306 on the shim tabs 302 without additional material and supplementedwith additional material at other locations.

The shim tabs 302 are aligned on a single plane when connected. In otherembodiments, the shim tabs 302 are stacked on an axis that goes throughthe center of the shim tabs 302. In some embodiments, the shim tabs 302are oriented at a rotational angle relative to one another. Otherarrangements are also contemplated.

FIG. 4 is a schematic view of a compound shimming system 400, accordingto one or more examples of the present disclosure. The compound shimmingsystem 400 includes an assembly jig 402 to secure a part 404. Theassembly jig 402 is a fixed frame or hanger to which the part 404 issecured. In another embodiment, the assembly jig 402 is a mobileplatform capable of orienting the part 404 during assembly. The assemblyjig 402 secures the part 404 relative to a multi-axis arm 406. Themulti-axis arm 406 includes an end-effector 408. The multi-axis arm 406moves the end-effector 408 relative to the part 404. The multi-axis arm406 moves relative to the part via a track 407 or other mobility system.The multi-axis arm 406 may include joints, articulations, or otherpositioning elements.

The part 404, in the illustrated embodiment, includes a stringer 410 anda rib flange 412 of an aircraft wing. Other embodiments include othertypes of parts for other systems and structures. The rib flange 412includes a joining region 414 where the rib flange 412 is secured to thepart 404 or another structure. The joining region 414 is shown in amagnified view.

The end-effector 408 applies shim tabs 416 to a location on the part404. The end-effector 408 applies the shim tabs 416 to the joiningregion 414. The end-effector 408 applies the shim tabs 416 in a firstlayer (i.e. a first shim tab 416 at a first location then a second shimtab 416 at a second location adjacent to the first location) and thenapplies a second layer of shim tabs 416 layered on top of some or all ofthe shim tabs 416 in the first layer. This process may continue untilthe desired dimensions are reached for each location in the compoundshim applied at the joining region 414 of the part 404. In otherembodiments, the shim tabs 416 of a given stack are layered to theprescribed height before forming the next stack of shim tabs 416.

In the illustrated embodiment of the joining region 414 of the part 404,the shim tabs 416 are applied in the vicinity of a fastener location(shown as a round hole amid the shim tabs 416). The fastener locationcan be a hole or aperture in the joining region 414 to facilitate afastener to join the part 404 to another part or component. The shimtabs 416 are illustrated with different patterns to indicate differentnumbers of layers of shim tabs 416 to achieve various thicknesses. Asdescribed above, the shim tabs 416 may be layered to achieve a thicknesscommensurate with a surface characteristic of the part 404 to reduceseparation between two parts at the joining region 414.

The end-effector 408 includes an inspection module to determine asurface characteristic of the part 404 at the joining region 414. Theinspection module includes an optical, sonic, tactile, or other scanningor imaging device. Furthermore, the inspection module includes anemission component and a sensor component. The emission component emitsa signal onto the joining region of the part 412 and a second part to bejoined to the part 412. The sensor component receives a reflectedemission from the part.

The inspection module sends data corresponding to the surfacecharacteristic of the part to a control module. The control moduleinterprets the data to create a compound shim layout or compound shimplan with a geometry corresponding to joining region and a gap that maybe formed by the joining of the part 412 with another part.

FIG. 5 is a schematic flow diagram of a method 500, according to one ormore examples of the present disclosure. The method 500 includesidentifying, at block 502, a first location on a first part to place afirst shim tab to form a first portion of a compound shim. In someembodiments, identification of the first location is determined by anassembly plan for the first part. In other embodiments, identificationof the first location is determined by scanning the first part.

At block 504, the first shim tab is applied to the first location on thefirst part with an end-effector. The shim tab may be applied using anadhesive or other tacking material or mechanic. For example, the shimtab may include an adhesive applied to one or both sides of the shim tabto facilitate adhesion at the part. In other embodiments, the shim tabis applied to an adhesive on the surface of the part. In someembodiments, the shim tab is applied to the part and an adhesive orsealant layer is applied over the shim tab or infused into a shim tabstack or compound shim to secure the shim tab to the part. Other mannersof securing the shim tab to the part are also contemplated.

At block 506, a second location is identified which is directly adjacentto the first location of the first part to place a second shim tab. Insome embodiments, the second location is identified based on a surfacecharacteristic of the first part. In other embodiments, the secondlocation is identified based on a pre-determined distance at which thesecond shim tab is to be placed from the first shim tab. In someembodiments, the distance is determined by a compound shim plan.

At block 508, the second shim is applied to the second location on thefirst part with the end-effector to form a second portion of thecompound shim. In some embodiments, as described above, the shim tabsare applied by separating each shim tab from a carrier material. Inother embodiments, the shim tabs are connected to one another and areseparated during or before applying the shim tab. In some embodiments,the end-effector applies the second shim tab in alignment with firstshim tab. In some embodiments, the shim tab is applied to an adjustedlocation based on a detection that the first shim tab is offset from thefirst location. In other embodiments, the end-effector applies thesecond shim tab with a gap between the first shim tab and the secondshim tab.

At block 510, a third shim tab is applied to the second shim tab at thesecond location to increase a thickness of the second portion of thecompound shim. In some embodiments, the third shim tab includes adhesiveon the surface applied to the second shim tab. In some embodiments, thesecond shim tab includes an adhesive on the surface of the second shimtab to which the third shim tab is applied. In some embodiments, thethird shim tab is aligned to match the geometry, and stack on top, ofthe second shim tab.

In the above description, certain terms may be used such as “up,”“down,” “upper,” “lower,” “horizontal,” “vertical,” “left,” “right,”“over,” “under” and the like. These terms are used, where applicable, toprovide some clarity of description when dealing with relativerelationships. But, these terms are not intended to imply absoluterelationships, positions, and/or orientations. For example, with respectto an object, an “upper” surface can become a “lower” surface simply byturning the object over. Nevertheless, it is still the same object.Further, the terms “including,” “comprising,” “having,” and variationsthereof mean “including but not limited to” unless expressly specifiedotherwise. An enumerated listing of items does not imply that any or allof the items are mutually exclusive and/or mutually inclusive, unlessexpressly specified otherwise. The terms “a,” “an,” and “the” also referto “one or more” unless expressly specified otherwise. Further, the term“plurality” can be defined as “at least two.”

Additionally, instances in this specification where one element is“coupled” to another element can include direct and indirect coupling.Direct coupling can be defined as one element coupled to and in somecontact with another element. Indirect coupling can be defined ascoupling between two elements not in direct contact with each other, buthaving one or more additional elements between the coupled elements.Further, as used herein, securing one element to another element caninclude direct securing and indirect securing. Additionally, as usedherein, “adjacent” does not necessarily denote contact. For example, oneelement can be adjacent to another element without being in contact withthat element.

As used herein, the phrase “at least one of,” when used with a list ofitems, means different combinations of one or more of the listed itemsmay be used and only one of the items in the list may be needed. Theitem may be a particular object, thing, or category. In other words, “atleast one of” means any combination of items or number of items may beused from the list, but not all of the items in the list may berequired. For example, “at least one of item A, item B, and item C” maymean item A; item A and item B; item B; item A, item B, and item C; oritem B and item C. In some cases, “at least one of item A, item B, anditem C” may mean, for example, without limitation, two of item A, one ofitem B, and ten of item C; four of item B and seven of item C; or someother suitable combination.

Unless otherwise indicated, the terms “first,” “second,” etc. are usedherein merely as labels, and are not intended to impose ordinal,positional, or hierarchical requirements on the items to which theseterms refer. Moreover, reference to, e.g., a “second” item does notrequire or preclude the existence of, e.g., a “first” or lower-numbereditem, and/or, e.g., a “third” or higher-numbered item.

As used herein, a system, apparatus, structure, article, element,component, or hardware “configured to” perform a specified function isindeed capable of performing the specified function without anyalteration, rather than merely having potential to perform the specifiedfunction after further modification. In other words, the system,apparatus, structure, article, element, component, or hardware“configured to” perform a specified function is specifically selected,created, implemented, utilized, programmed, and/or designed for thepurpose of performing the specified function. As used herein,“configured to” denotes existing characteristics of a system, apparatus,structure, article, element, component, or hardware which enables thesystem, apparatus, structure, article, element, component, or hardwareto perform the specified function without further modification. Forpurposes of this disclosure, a system, apparatus, structure, article,element, component, or hardware described as being “configured to”perform a particular function may additionally or alternatively bedescribed as being “adapted to” and/or as being “operative to” performthat function.

The schematic flowchart included herein are generally set forth aslogical flowchart. As such, the depicted order and labeled steps areindicative of one embodiment of the presented method. Other steps andmethods may be conceived that are equivalent in function, logic, oreffect to one or more steps, or portions thereof, of the illustratedmethod. Additionally, the format and symbols employed are provided toexplain the logical steps of the method and are understood not to limitthe scope of the method. Although various arrow types and line types maybe employed in the flowchart, they are understood not to limit the scopeof the corresponding method. Indeed, some arrows or other connectors maybe used to indicate only the logical flow of the method. For instance,an arrow may indicate a waiting or monitoring period of unspecifiedduration between enumerated steps of the depicted method. Additionally,the order in which a particular method occurs may or may not strictlyadhere to the order of the corresponding steps shown.

The present subject matter may be embodied in other specific formswithout departing from its spirit or essential characteristics. Thedescribed embodiments are to be considered in all respects only asillustrative and not restrictive. All changes which come within themeaning and range of equivalency of the claims are to be embraced withintheir scope.

What is claimed is:
 1. An apparatus comprising: a supply spool carryinga roll of shim tabs on a carrier material, wherein the shim tabscomprise a first shim tab, a second shim tab, and a third shim tab; acollection spool carrying a roll of the carrier material without shimtabs; and an applicator configured to: receive the first shim tab on thecarrier material from the supply spool; apply the first shim tab to afirst location on a part; receive the second shim tab on the carriermaterial from the supply spool; apply the second shim tab to a secondlocation directly adjacent to the first location on the part to form acompound shim; receive the third shim tab on the carrier material fromthe supply spool; and apply the third shim tab to the second shim tab atthe second location; wherein: the supply spool is rotatable about afirst axis to dispense the shim tabs on the carrier material; thecollection spool is rotatable about a second axis to receive the carriermaterial without shim tabs from the applicator; the first axis is fixedrelative to the second axis; and the first axis and the second axis areco-movable with the applicator.
 2. The apparatus according to claim 1,further comprising: a first motor, selectively operable to rotate thesupply spool; and a second motor, selectively operable to rotate thecollection spool.
 3. The apparatus according to claim 2, furthercomprising an extension structure that is selectively actuatable totranslationally move the applicator relative to the first axis and thesecond axis.
 4. The apparatus according to claim 1, wherein theapplicator is configured to separate the first shim tab, the second shimtab, and the third shim tab from the carrier material.
 5. The apparatusaccording to claim 1, wherein the applicator is configured to separatethe first shim tab from the second shim tab.
 6. The apparatus accordingto claim 1, further comprising a control module that is configured tocontrol delivery of the first shim tab, the second shim tab, and thethird shim tab to the applicator.
 7. The apparatus according to claim 1,wherein the applicator comprises a roller.
 8. The apparatus according toclaim 1, wherein the first shim tab, the second shim tab, and the thirdshim tab have a uniform geometry and thickness.
 9. The apparatusaccording to claim 7, wherein the roller is deformable.
 10. A systemcomprising: an assembly jig configured to secure a first part; aninspection module configured to generate inspection data describing asurface characteristic of at least the first part at a joining regionwhere the first part is to be joined with a second part; a controlmodule configured to generate a compound shim plan corresponding to thejoining region of the first part based on the inspection data; amulti-axis arm configured to move relative to the assembly jig inresponse to input from the control module; and an apparatus coupled tothe multi-axis arm and comprising: a supply spool carrying a roll ofshim tabs on a carrier material, wherein the shim tabs comprise a firstshim tab, a second shim tab, and a third shim tab; a collection spoolcarrying a roll of the carrier material without shim tabs; and anapplicator configured to: receive the first shim tab on the carriermaterial from the supply spool; apply the first shim tab to a firstlocation on the first part, receive the second shim tab on the carriermaterial from the supply spool; apply the second shim tab to a secondlocation on the first part directly adjacent to the first location onthe first part to form a compound shim; receive the third shim tab fromthe supply structure; and apply the third shim tab to the second shimtab at the second location wherein: the supply spool is rotatable abouta first axis to dispense the shim tabs on the carrier material; thecollection spool is rotatable about a second axis to receive the carriermaterial without shim tabs from the applicator; the first axis is fixedrelative to the second axis; and the first axis and the second axis areco-movable with the applicator.
 11. The system according to claim 10,wherein the inspection module is further configured to monitor theapplication of the first shim tab and to adjust the application of thesecond shim tab in response to monitoring the application of the firstshim tab.
 12. The system according to claim 10, wherein the apparatusfurther comprises a motor that is selectively operable to rotate thesupply.
 13. The system according to claim 12, wherein the apparatusfurther comprises a second motor that is selectively operable to rotatethe collection spool.
 14. The system apparatus according to claim 10,wherein the apparatus further comprises an extension structure that isselectively actuatable to translationally move the applicator relativeto the first axis.
 15. The system according to claim 10, wherein theapplicator comprises a roller.
 16. The system according to claim 15,wherein the roller is deformable.
 17. The apparatus according to claim1, wherein each of the first shim tab, the second shim tab, and thethird shim tab has a polygonal geometry.
 18. The apparatus according toclaim 1, wherein each of the first shim tab, the second shim tab, andthe third shim tab has a hexagonal geometry.
 19. The apparatus accordingto claim 1, wherein the shapes of the first shim tab, the second shimtab, and the third shim tab are the same.
 20. The system according toclaim 10, wherein a thickness of the first shim tab, the second shimtab, and the third shim tab is the same.